Years ahead of its anticipated opening date, Hong Kong’s visual-arts museum M+ received a significant boost on Tuesday when collector Uli Sigg, a former Swiss ambassador to China, donated the majority of his Chinese contemporary art collection to the institution in a gift valued at $163 million.

Mr. Sigg said that China’s freedom-of-expression “constraints” moved him to give his collection to a Hong Kong museum rather than one in the mainland. He added that he hoped his contribution would act as a “vote of confidence” in the city’s bid to become a global art hub. Hong Kong is currently the world’s third largest art-auction market after London and New York, while its international art fair, Art HK, has been acquired by Art Basel.

The museum, part of the city’s West Kowloon Cultural District, plans to open its doors in 2017.

Corrections & Amplifications: An earlier version of this article incorrectly spelled Zeng Fanzhi’s given name.